There is an unmarked building somewhere along the eastern seaboard that contains more pieces of WWE history than a dozen WrestleMania highlight reels. It is the WWE vault and inside the sprawling, cavernous building sits crates teeming with championship titles, wardrobes filled with unmistakable ring gear and even a Punjabi prison.

The warehouse is a wonderland for any sports-entertainment fan, but it’s harder to get into than Yale. Luckily, WWE Classics has a friend on the inside. WWE’s resident archivist Benjamin Brown used his security clearances to grant us access to WWE’s best kept secret and then offered us a guided tour through wrestling history.

This month, we looked at caskets, urns and even a certain symbol used by The Undertaker during his two decades of destruction in WWE. Join us on our journey to the dark side. Just don’t touch anything. ( PHOTOS)

Bat wings from Survivor Series 1996

Mick Foley is a sentimental favorite of the WWE Universe today, but when The Hardcore Legend debuted in WWE in 1996, he was a dangerous lunatic known as Mankind. Quickly targeting The Undertaker upon his arrival, the masked maniac pushed The Deadman to his edge in bizarre stipulation matches like the Boiler Room Brawl and a macabre Buried Alive Match. ( WATCH) Mankind even played a part in Undertaker’s most infamous betrayal when manager Paul Bearer turned his back on The Phenom at SummerSlam 1996.

Leading into a return match against his deranged rival at November’s Survivor Series, The Undertaker was in the strange position of underdog. He had been devastated and deceived and the WWE fans in New York City’s Madison Square Garden had seemingly lost faith in his abilities. And then he entered. Avoiding his usual funeral march from the entryway, The Demon from Death Valley descended from the rafters of The World’s Most Famous Arena with his arms spread open wide in entrance attire that resembled bat wings. ( WATCH) It was a stunning image to behold and a moment that made it clear that the Superstar who once terrified the WWE Universe was now its greatest hero.

Demonic symbol from Raw on Dec. 7, 1998

The Undertaker didn’t do polite, but he was never as wicked as he was in 1998. Then the satanic leader of a cult of demons he dubbed his Ministry of Darkness, The Deadman waged a dark war against “Stone Cold” Steve Austin and Mr. McMahon’s family with the depraved intentions of a man turned monster.

As The Phenom’s rivalry with The Texas Rattlesnake roared on, the two Superstars faced off in a wild tag team main event on the Dec. 7, 1998, edition of Raw, pitting The Undertaker & The Rock against Austin & Mankind. As the enemies brawled at ringside, The Deadman knocked “Stone Cold” silly with a steel chair and then carried his limp body to the top of the entrance ramp. There, The Undertaker was met by a group of druids dressed in black cloaks who tied Austin to the demonic symbol seen above. The emblem was then hoisted into the air so the WWE Universe could see what The Deadman had done to their hero. Few moments in WWE history have ignited as much controversy.

Casket from 1994's "Hart Attack Tour"

At Survivor Series 1994, The Undertaker gained retribution against the villainous Yokozuna in a Casket Match after being destroyed by the massive Superstar in the same type of bout at that year’s Royal Rumble. ( WATCH) It was a major victory for The Phenom, who received some backup from none other than Chuck Norris during the bout, but it wasn’t the first time he got his cold, dead hands on Yokozuna that fall.

In the weeks leading up to November’s Survivor Series, WWE held a series of Live Events they dubbed “The Hart Attack Tour.” The shows, which were held everywhere from East Rutherford, N.J., to Montreal, regularly featured a Casket Match main event between the 600-pound Yokozuna and The Deadman. In honor of the special bouts, Undertaker constructed a unique coffin for his opponent, which manager Paul Bearer described as “double wide, double deep.” More often than not, the enormous Japanese Superstar ended up locked inside at the end of the night.

Entrance attire from WrestleMania XIV

Of all the historic WrestleMania contests that encompass The Undertaker’s legendary Streak, The Deadman’s most personal bout was undoubtedly his WrestleMania XIV match against his brother, Kane. Thought to be long dead by The Undertaker, The Devil’s Favorite Demon made his first WWE appearance at Badd Blood on Oct. 5, 1997, and attacked The Deadman during his Hell in a Cell Match against Shawn Michaels. For months, The Undertaker refused to face his half-brother, but when Kane and Paul Bearer locked The Phenom in a casket and set it on fire at Royal Rumble 1998, The Deadman finally had good reason to fight his flesh and blood.

The Undertaker defeated Kane after three Tombstones at WrestleMania XIV, but the enduring image of this landmark first showdown remains The Deadman’s entrance. Led to the ring by a gathering of druids who carried brilliant torches and chanted in eerie harmony, The Undertaker walked through fire and lightning to meet his younger brother and confirmed something that the WWE fans already knew — this night was going to be epic. ( WATCH)

Concrete Crypt from Great American Bash 2004

Of all the twisted brawls The Undertaker has fought his way through, none was as unusual as 2004’s Concrete Crypt Match. A handicap contest pitting The Deadman against both Dudley Boyz, the bout was made after Bubba & D-Von kidnapped Paul Bearer to make an impact on SmackDown. The Undertaker was presented with the option to join up with the tag team and the depraved Paul Heyman, but when The Deadman refused, he was challenged to a match at Great American Bash 2004 where if he lost, Bearer would be entombed in cement.

The severity of the stipulation was made clear before the bout began as Paul Bearer was shown shackled to a chair inside a glass chamber. Above the macabre manager was a cement truck ready to pour thousands of pounds of concrete down on top of him should The Undertaker lose. Why local authorities didn’t get involved to stop this sick plot is unclear, but it hardly mattered as The Phenom managed to overcome both Dudleyz and save his manager. Or did he? As The Deadman walked away from the ring, he grabbed a microphone and said, “Paul, I have no other choice,” before pulling a lever and willfully burying his former friend alive. ( WATCH)

Urn from WrestleMania XI

The Undertaker entered his WrestleMania XI bout against King Kong Bundy without his mythical urn in the possession of manager Paul Bearer. Earlier that year at Royal Rumble 1995, Irwin R. Schyster had “repossessed” the mysterious container while Bundy distracted The Deadman in the ring. With the urn no longer in his control, it was said that The Undertaker now lacked the supernatural strength and stamina he once held.

Bolstered by this belief, the 444-pound Bundy threw all of his weight at The Deadman in a mad attempt to break The Undertaker’s Streak before it could reach 4–0. Of course, the Superstar who Gorilla Monsoon once referred to as a “walking condominium” failed to stop The Phenom. Although The Deadman was unable to recapture his urn (Kama of The Million Dollar Corporation ran off with it), he beat Bundy after slamming the monster and then upending him with a huge flying clothesline. ( WATCH)

Casket from WrestleMania 22

The Undertaker’s 20-0 Streak on The Grandest Stage of Them All didn’t come easily. Over the course of his 20 WrestleMania appearances, The Demon from Death Valley had to overcome super heavyweights like Sid, Diesel and Mark Henry, who The Undertaker challenged in a Casket Match at WrestleMania 22.

Competing in this twisted type of bout for the first time at The Show of Shows, The Phenom was seeking retribution against the man who screwed him out of the World Heavyweight Title on SmackDown. The Deadman could not overpower his opponent, but he proved he had more heart than The World’s Strongest Man. Using his superhuman agility, The Undertaker crushed Henry on the outside of the ring by leaping over the top rope before nailing him with the Tombstone and stuffing him into this coffin. ( WATCH)

Not done digging through WWE's vault? Check out some of our earlier expeditions into the warehouse:

Ring jackets | Rare championships | Five cool items from Raw